1. Field of the Invention
The present invention relates to an image forming device which can staple printed documents, a method for printing and a program recording medium.
2. Description of Related Art
FIG. 6 is a schematic diagram showing a conventional image forming device having a stapler, a paper feeding passage thereof, and printed documents being stapled. In FIG. 6, when printing on one side, paper 1 in a paper feeding tray 2 is fed one sheet at a time as symbol (1) shows. Then an image is printed on the paper 1 by an image forming portion 3 constituted by a photosensitive drum or the like as shown by symbol (2). The printed paper 1 is stacked in an intermediate tray 4, pushed to the front in FIG. 6 for aligning its end when a page number reaches a desired number, and stapled by a stapler 5. Finally, a stapled sheaf of paper 6 is discharged in a catch tray 7 as shown by symbol (3).
In this device, printing is performed from the first page of the document in order and the pages stacked in the intermediate tray 4 face-down (hereinbelow, simply referred to as the “face-down process”). Thus the sheaves of paper 6 stapled into a desired number of sheets are stacked in the catch tray 7. The sheaf of paper 6 is stapled at a staple point 8 located at the upper left of the sheaf with respect to the image printed thereon.
When printing on both sides, an image of an odd-numbered page is printed on one side of the paper 1. Then the paper 1 is reversed and an image of an even-numbered page is printed on the other side of the paper 1. The paper both sides of which are printed onto is fed to the intermediate tray 4 and stacked therein face-down.
An image forming device which staples using post-processing equipment has been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2000-44109). An image forming device which can move its staple point when printing on one side, by stapling after reversing the paper when it is placed in landscape orientation has been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2003-337508). In addition, an image forming device in which it is made possible for assembly and fixing of jams to be performed easily by having a first unit including an intermediate tray and a second unit with a carrying and branching function has also been proposed (see, for example, Japanese Unexamined Patent Application, Publication No. 2001-235916).
In low-cost image forming devices which can perform stapling like the one shown in FIG. 6, only one stapler 5 is provided and it is fixed at a predetermined position. In a case where the stapler 5 is fixed, the staple point 8 on the sheaf of paper 6 is fixed at the upper left thereof with respect to the printed image as shown in FIG. 6. Therefore, the sheaf is stapled at a position which the user does not desire for certain image orientations (portrait or landscape) and feeding directions (short-edge feed or long-edge feed, which will be described later).
For example, in FIG. 7, the staple point 8 is set at the upper left of the paper with respect to the printed image when the image is fed lengthwise (portrait-long edge feed). When the image is fed upside down, the staple point 8 is set at the bottom right of the paper with respect to the printed image as shown in pattern A. In cases where the image is fed at a 90° rotation with respect to the original direction such as in pattern B (portrait-short edge feed) or pattern C (landscape-long edge feed), the staple point 8 is set at the upper right or bottom left of the paper with respect to the printed image. The staple point 8 is set at the upper left or bottom right of the paper with respect to the printed image in pattern D (landscape-short edge feed).
That is, in the cases shown in FIG. 7, the staple point 8 is always fixed on one diagonal line on the paper. In addition, the staple point 8 is set at the upper right or bottom left when the image is fed in a direction perpendicular to the lines of text. Most users generally desire the staple point 8 to be at the upper left of the sheaf of the paper 6 with respect to the image printed thereon. Accordingly, there is a problem in that a document cannot be stapled at a desired position in image feeding conditions like pattern B or pattern C shown in FIG. 7. Rotating the paper so that it is at a 90° rotation is a possible solution to this problem. However, this problem cannot be avoided in a case where paper of a large size such as A3 paper is used because such large sized paper cannot be turned.